weird idle problem - Honda Prelude Forum

toofastprelude · 07-18-2003, 05:05 PM

first off i did a esearch and all of my hoses have been replaced and it still fluctuates. i have the idle screw turned all the way down as far as it can go and the idle still bounces between 1k to 2k rpm. i have the coolant mod done and revesed it and did not solve the problem. if i put my finger over the 9 oclock position on the tb it stops and idles at 1k. also if i press the brake all the way in hard at idle it will stop and idle normal. what would you guys think the problem is, i have searched and searched and still came up with nothing

joshmv · 07-18-2003, 06:37 PM

i'm anxious to see the answers too, that is EXACTLY what mine does, it sucks when it idles at 2k, you look like an idiot driving around. I think it's the computer but we'll see what these guys think.

Josh

UZ 2 B AUTO · 07-18-2003, 06:44 PM

have you tried cleaning your iac valve...fixed the problem in my 5 gen.

buffmanextreem · 07-18-2003, 06:50 PM

^^^Same with me. My idle was jumping up and down and all i did was remove the iac clean it out and the problem was solved.

UZ 2 B AUTO · 07-18-2003, 06:51 PM

oh yeah dont forget to plug the sensor back in when you are finished..i did this and i thought i had fvcked something up when i cleaned it cuz it drove like ass LOL

toofastprelude · 07-18-2003, 11:06 PM

everything on my car is clean and works fine with no check engine light or anything, everything is ok except for my idle. but when the brake is pressed in all the way in idle normal. is there anything more i can bypass or anyone know whats wrong with my lude? honda wants 68 bucks per hour to check it out, i had them look at it for an hour and they came up with no answers so they tried feedin me a line of bull**** about my intake and coolant mod bypass. please someone help!!!

matt0wns · 07-18-2003, 11:12 PM

my car did the same, but i had to actually change the iac all together. But that was for sure the problem. Anyone who has an iac for an h22 please let me know... i'd like to have a spare.

thanx

joshmv · 07-18-2003, 11:13 PM

umm, is the iac valve the the thing on the side of the intake manifold that you can just take off and clean. if i remember right it's about 1" x 1" and has a vacuum line attached? if it is what do I need to look out for when I'm taking it off the manifold and putting it back on, I'm not usually good with much engine work.

toofastprelude · 07-19-2003, 07:20 PM

i cleaned the iac valve and no difference, still weird idle. what i am wonderong about is when i press the brake in all the way the jumping idle stops and its ok again. are the brakes somehow tied into some type of sensor on the intake manifold or something?

Hazardous Sport · 07-19-2003, 10:06 PM

Can anyone snap a pic or something, i dont know where its located....plus i dont mean to sound stupid but what does IAC stand for exactly?

toofastprelude · 07-19-2003, 11:43 PM

dle air control valve, its on your intake manifold right under the throttle cable, has a black cylinder on the end of it with 2 wires onit.

B|OhAzA|2D · 07-20-2003, 04:24 PM

I had a similar problem, but also it was effecting how it was driving , couldnt move without it bogging down.

It was that Idle Air Control Valve, Just replaced it and car idled fine since then, Wasnt cheap either about $240 is what I payed, if I remember right.

toofastprelude · 08-14-2003, 08:19 PM

well i bought a new iac valve and throttle body with new sensor and problem still not solved. still bounces between 1k-2k rpm. i will stop still when i press the brake in all the way very hard or when i put my finger over the 9 oclock position on the tb. i might just put a piece of alum or alum weld epoxy and fill the 9 oclock hole in and see what happens. i have a extra tb just sittin here if i mess it up so i guess its worth a shot, any other suggestions

attilude93 · 08-15-2003, 10:36 PM

toofast,
Try blocking off your fast idle valve underneath the TB. If you just do the coolant bypass without blocking off the fast idle valve, then your car will idle like crazy. The fast idle valve is located directly underneath the TB held on with 3 10mm bolts. Just cover it up with a piece of copper or metal, or cardboard if you dont have access to any metal. I believe there is a writeup in the general FAQ. Just search for coolant mod or TB block off plate.

toofastprelude · 08-17-2003, 11:46 PM

it has been blocked from day 1, just fyi i started making my neew tb. will be 75 mm with port matched im and bypasses most emissions and a lot of vacuum lines. i will keep posted on the progress

B|OhAzA|2D · 08-20-2003, 04:39 PM

Maybe......

I just saw this again, and it sounds like you moved on but....

Did you try your other tb?

I heard somewhere (someone else might have better info on this more than I ) That where the TB valve sits inside, along the wall of its location is a lining or seal that is located their when the valve is in the closed position.

I dont know if this is why you might find that if you put ur finger over the hole that is may be replecating what the ring on the wall is suppose to do

Of course this is an idea and someone might have better info, but I always heard that to make sure that is not damaged

??

Si_g · 08-23-2003, 12:45 AM

Someone else started a thread about the same problem, a while ago, i posted the answer i found, cause i had the same thing happen to me. My problem was the idle control valve, located inside a lil conpartment ( i believe thats what its called), attached to the bottom of the throttle body. my motor mounts were bad, which cause my engine to shake a lot, so that thing got really loose, so i opened it, and i fell out. if you had the same thing i had, then take our your throttle body, then, look on the side of the bottom piece, there should be 2 lil screws covering a bronze lookin cover plate, its really small, like an inch and a half or so wide. take those 2 screws out, and there will be a white lil thing in there, with a spring around it, it should be loose, at least mind was, since it feel out, all i did my tighten it back up, and put the whole thing back 2gether, of course i changed my motor mounts b4 i did that, and i put it back 2gether, and idle has been perfect between 500 and 750.